Ethylenediamine → 9-bromo-5H-pyrazino[2,3-b]indole

HRID 1882220Notes

Reaction equation

HRID 1882220 reaction equation
C([N:4]1[C:12]2[C:7](=[C:8]([Br:13])[CH:9]=[CH:10][CH:11]=2)[C:6](=O)[CH2:5]1)(=O)C.BrBr.[CH2:17]([NH2:20])[CH2:18][NH2:19].C(N(CC)CC)C>C(Cl)Cl.CO>[Br:13][C:8]1[C:7]2[C:6]3[N:20]=[CH:17][CH:18]=[N:19][C:5]=3[NH:4][C:12]=2[CH:11]=[CH:10][CH:9]=1

Participants

7

Reactant 4

HCID 3301EthylenediamineHCID 8471TriethylamineHCID 24408BromineHCID 532432881-Acetyl-4-bromoindolin-3-one

Product 1

HCID 588800869-bromo-5H-pyrazino[2,3-b]indoleYield 55.2%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 6344DichloromethaneSolvent

Procedure

1-Acetyl-4-bromo-1,2-dihydro-indol-3-one (460 mg, 1.81 mmol) was dissolved in CH2Cl2 (8 mL). Bromine (111 μL, 2.2 mmol) was added slowly, and the reaction stirred for 20 min and then was concentrated in vacuo. The residue was dissolved in THF (8 mL). Ethylenediamine (244 μL, 3.6 mmol) was added, and the reaction stirred for 16 h at r.t. Triethylamine (2 mL) and MeOH (4 mL) were added, and the reaction stirred while left open to air for 24 h. The solution was concentrated in vacuo and purified by silica gel chromatography (8% MeOH/CH2Cl2) to give 248 mg (55%) of the title compound as a red solid. MS (ES) [m+H] calc'd for C10H6BrN3, 248, 250; found 248, 250.

Workup

  1. concentrationwas concentrated in vacuo
  2. dissolutionThe residue was dissolved in THF (8 mL)
  3. stirringthe reaction stirred for 16 h at r.t
  4. stirringthe reaction stirred
  5. waitwhile left open to air for 24 h
  6. concentrationThe solution was concentrated in vacuo
  7. custompurified by silica gel chromatography (8% MeOH/CH2Cl2)

Sources & evidence

ORD record
ord-9e488971e4444541a6a0328310a4d562
Source dataset
uspto-grants-2012_11
Patent number
US08318939B2

Reaction notes

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